Understanding the function of marine microbes

May 11th, 2021

Eric on the dock about to set out on a 63-day journey to sample microbes in the South Pacific.

While working as a postdoc with the Environomics Future Science Platfrom at CSIRO, Eric Raes sailed to Antarctica and the warm equatorial waters of the South Pacific on board CSIRO’s Research Vessel Investigator. During the two month voyage he collected hundreds of water samples from the ocean. He used them to understand how microbial biodiversity in our oceans influences functional diversity (the work microbes do), and how these are related to energy production in the ocean.

In their paper recently published in Nature Communications, Eric and a team of researchers show how a bacterial marker gene (16S rRNA) can be used to infer latitudinal trends for metabolic pathways when carrying out marine monitoring.

Ocean microbes catalyse important ecosystem services, including oxygen production, carbon sequestration cycling of elements at the base of the marine food web. There is much we don’t know about the interactions between different microbial taxa, the functions they execute and their role in marine ecosystems.

Eric and the team looked at a transect spanning 7000km in the South Pacific Ocean. They inferred ten metabolic processes from 16S rRNA gene sequences and 11 corresponding shotgun metagenome samples. These were related to metabolic processes including energy production, temperature-regulated thermodynamic effects, coping strategies for nutrient limitation and organic matter degradation.

Their study highlighted the ability to query metabolic pathways in existing and future 16S rRNA gene datasets on a global scale. This establishes the opportunity to test hypotheses regarding how biodiversity influences functional diversity and how these are related to energy production in the ocean. Deriving these metabolic profiles from 16S rRNA gene datasets obtained by oceanic sampling programs on a global scale may provide a better understanding of the components of a resilient marine ecosystem and of how that resilience is tested through existing and emerging environmental stressors.

Read about Eric’s work in The Conversation. https://theconversation.com/like-the-oceans-gut-flora-we-sailed-from-antarctica-to-the-equator-to-learn-how-bacteria-affect-ocean-health-155478

Read the paper in Nature Communications. https://www.nature.com/articles/s41467-021-22409-4